The activity or effectiveness of hair shaping preparations is based mainly on the inclusion therein of an agent for softening and relaxing the keratin protein present in hair by reducing the disulfide (S--S) linkages of keratin which covalently link adjacent polypeptide chains (K). The hair fiber is wound on rods to achieve the desired waving effect or manipulated into a straightened condition and allowed to remain wetted with the reducing lotion for a desired period, after which the reducing lotion is rinsed off and finally oxidized with a neutralizing solution or air oxidized.
Basically, hair is softened and swelled by the use of a mild alkaline reducing agent. Cleavage of at least some of the disulfide bonding to form the corresponding cystine residue is necessary to allow for molecular rearrangement which takes place during the hair fiber molding operation. The reductive fission of hair disulfides generally causes reddening of the scalp area and damage to the hair fiber, particularly hair which has been bleached, tinted or otherwise damaged. Current hair structure altering lotions which provide relaxation of imposed stress include aqueous solutions of alkaline mercapto compounds, sulfites or bisulfites at a pH of between 4 and 10. In order to obtain a permanent effect, particularly in hair straightening, it is often necessary to introduce the active agent in relatively high concentrations with the result that the reducing lotion is provided at almost the limit of its physiological compatibility or tolerability.
Damage to hair is increased where heat waving, as opposed to cold waving, is employed. Of the reducing agents currently in use, the thioglycolates or thioglycolic acid, dithioglycolic acid and mercapto compounds such as ammonium thioglycolate, glyceryl monothioglycolate, mercaptopropionic acid and mercaptoethyl amine are most often employed in the professional waving or hair straightening of the present invention. In lieu of the heat waving or cold waving, the oxidizing waving of the present invention can be effected by oxidizing the mercaptan with an agent, such as hydrogen peroxide, an iodate or a bromate. This oxidizing solution is typically called an activator.
The reducing agent used in exothermic perms is typically a mercaptan (RSH), such as ammnonium thioglycolate (ATG). The chemistry involved in the reaction of a mercaptan with the cystine disulfide bonds (KSSK) in the hair fiber to foden a disulfide, such as dithioglycolate and a keratin residue is illustrated by the following chemical equation: EQU KSSK+2 RSH.fwdarw.2 KSH+RSSR
The reduced keratin is rebonded with the hair in a curled configuration to effect a permanent set. This rebonding is accomplished by the action of a chemical oxidation agent, commonly referred to as the permanent wave neutralizer. Typically, the oxidizing agents used in most neutralizers are hyrodgen peroxide and sodium bromate. The chemical oxidation (neutralization) reaction is illustrated in the following reaction: EQU 2 KSH+O.sup.- .fwdarw.KSSK+H.sub.2 O
The exothermic reaction of the present invention is illustrated in the following reaction: EQU 2 RSH+H.sub.2 O.sub.2 .fwdarw.RSSR+2H.sub.2 O+heat
The di-thio formed acts to form a reverse equilibrium reaction which serves to significantly slow the reduction of the keratin to effect a "stop action" of the permanent waving process. This provides better control of the perming effect.
U.S. Pat. No. patent 4,793,994 discloses a cold wave permanent wherein a N-alkyl lactam is incorporated into a hair perming lotion. One of the effects of the addition of the lactam is a conditioning effect on the hair. The permanent wave composition contains a waving solution, which is a reducing solution that can contain ammonium thioglycolate (ATG) and/or glyceryl monothioglycolate (GMT). GMT is known to be a less active reducing agent and is suitable for bleached, permed or damaged hair. The permanent wave composition contains a neutralizing solution containing hydrogen peroxide. This lactam may be used in cold or hot waves.
U.S. Pat. No. 4,158,704 discloses a method of permanent waving which eliminates the subjective judgment of the operator in determining the conditions for waving. This method is used with cold or hot waves, wherein the waving lotion is a reducing lotion which may contain AGT and/or GMT. A neutralizing solution is used containing an oxidizing agent, such as peroxide. The method involves a numerical rating the concentration of the waving solution, the pH of the solution, the condition of the hair and the porosity of the hair. Based on an evaluation of the above four parameters, the time and the temperature of the perm is determined.
U.S. Pat. No. 4,963,349 discloses a permanent wave solution employing a 1,3-alkyldiol in its reducing solution. The alcohol solution provides a permanent wave solution employing ATG at a pH in the same acidic range as the isoelectric point of hair (pH 3 to 5), or a five minute permanent wave with either an acid or alkaline solution. The use of GMT is discouraged as an "expensive chemical which must be packaged separately." The perms are hot or cold waves.
U.S. Pat. No. 4,273,143 discloses a permanent wave solution that can be used in conjunction with an exothermic wave, having a waving lotion suitable for simultaneous use on both bleached and unbleached hair containing a lipoidal alkyl chain having ten or more carbon atoms and a disulfide derivative of a mercaptan with a substituent group. The preferred compounds contain a quaternary ammonium group and a dithio derivative of a thioglycolate.
None of the above references disclose the present permanent wave solution for exothermic permanent waving.